a nugget of gold

Although heavy, and gold, this nugget contains many impurities. With some care and skill, however, it could be refined to pure gold.

It is a nugget of gold.
It weighs a few ounces.

You identify a nugget of gold.
It weighs five ounces, and it is worth about one lauren, seven celeb, and fifty busc.
Its keywords are nugget and gold.